1. Field of the Invention
The present invention relates to a gate valve apparatus for a vacuum-processing device.
2. Description of Related Art
Generally in gate valves the valve rod connected to the valve is driven by a link mechanism whereby the open/close operation of the flow path port is performed. In conventional gate valves, when the flow path port is to be closed, the valve is acted upon directly to move along the direction in which the valve rod extends. As a result, the valve is moved to a position that opposes the valve seat. Thereafter, the valve is push pressured to the valve seat. In this way, a conventional gate valve comprises a direct-acting link mechanism for the purpose of moving the valve in the direction in which the valve rod extends.
FIG. 6, FIG. 7 and FIG. 8 show the cross-sections of a conventional gate valve configuration. FIG. 6 is a diagram which shows the cross-section parallel to the valve seat of the gate valve. FIG. 7 and FIG. 8 are diagrams which show the cross-section orthogonal to the valve seat of the gate valve. FIG. 6 and FIG. 7 show the state when it is opened and FIG. 8 shows the state when it is closed.
As shown in FIG. 6, FIG. 7 and FIG. 8, the valve 10 is housed in the inner part of the valve box 14. The valve box 14 is provided on a fitted or fixing plate 20. One end of a drive shaft 12, as a valve rod, is connected to the valve 10. The other end of the drive shaft 12, by way of an opening 16 formed in the lower part of the valve box 14, leads out to the exterior of the valve box 14. The drive shaft 12 extends in a direction parallel to the valve seat of the circumferential edge of a flow path port 18 which opens to a side part of the valve box 14. A link mechanism for driving the drive shaft 12 is provided below the fitted plate 20. Using this link mechanism, the drive shaft 12 is operated whereby, by the movement of the valve 10 interlocked therewith, opening and closing of the flow path port 18 is performed. The valve 10, when closed, is in a state in which it is seated on the valve seat.
Next, a description of the configuration of the link mechanism will be given. Two mutually parallel plates 22 connect between the fitted plate 20 and a base plate 44. These plates 22 are provided in a state in which they are parallel with the direction in which the drive shaft 12 extends. The position in which the drive shaft 12 is deployed is between these plates 22.
Direct-acting cylinders 24 are provided on one end side of the plates 22, respectively, and the drive shaft 12 is provided on the other end side of the plates 22, respectively. The direct-acting cylinders 24 are fitted or fixed to the lower surface of each of the fitted plates 20 by way of cylinder-fitting blocks 32 of the same thickness.
Shafts 26, to which is attached a flange, are housed in the inner part of the above-noted direct-acting cylinders 24 in such a way as to be able to slide in the same direction as the direction in which the drive shaft 12 extends. The direct-acting cylinders 24 comprise two air ports. When air is introduced into the lower-end side air port 28 the shaft 26 rises. When air is introduced to the upper-end side air port 30 the shaft 26 lowers.
Power transmission plates 34 are connected to the lower end of the shafts 26 in a parallel state to the fitted plate 20. These power transmission plates 34, accompanying the rise/lower movement of the shafts 26, can be raised and lowered along the plates 22. Spring parts 36 are provided in the center of the power transmission plates 34. The lower end of the drive shaft 12 is supported on the power transmission plates 34 by way of the spring parts 36.
A shaft guide 38 is attached to a predetermined position in the center region of the drive shaft 12. Two pulleys 40 are provided in the shaft guide 38. These pulleys 40 are supported on the same axis. These pulleys 40 perform a rolling movement along long-holes 42 formed in the plates 22. Accordingly, the drive shaft 12 is able to have straight movement along the long-holes 42 together with the shaft guide 38. In addition, the drive shaft 12 and shaft guide 38 can perform rotation movement with the pulleys 40 forming the axis. Stoppers 60 and 62 are respectively provided in the fitted or fixing plate 20 side and direct-acting cylinder 24 side of the long-holes 42 and, as a result, the range of straight movement of the drive shaft 12 and shaft guide 38 is regulated.
The shaft guide 38 and the fitted plate 20 are coupled by a bellows 46. The drive shaft 12 is deployed in a state in which it is inserted in the bellows 46. A section of the opening 16 of the valve box 14 is sealed by the bellows 46 so the pressure state within the valve box 14 is maintained.
Power introducing plates 52, which comprise mutually parallel and opposing plates, are fixed to the power transmission plates 34. The lower end of the drive shaft 12 is enclosed in a state in which it has freedom to swing between the plates of the power introducing plates 52. In addition, through-holes which extend in a direction parallel to the axis of the above-noted pulleys 40 are formed in the lower end of the drive shaft 12, and a cam shaft 48 is inserted into these holes. Cylinder-shaped cams 50 are formed in both ends of this cam shaft 48, respectively. These cams 50 are fitted into holes 54 formed in the plates of the power introducing plate 52. The cams 50 can be rolled along the holes 54. The shape of the holes 54 is formed in such a way that the roll direction of the cams 50 is a state in which it is slightly inclined from the direction in which the drive shaft 12 extends, at the time of opening, to the flow path port 18 side.
Furthermore, power introducing plate guides 56 are arranged on the both sides of power introducing plates 52, respectively, and are apart therefrom, respectively. These power introducing plate guides 56 are fixed to the power transmission plates 34. Two pulleys 58 are supported by these power introducing plate guides 56, and these pulleys 58 can perform a rolling movement along a long hole 63 formed in the plates 22. These power introducing plate guides 56 are provided with the objective of reducing the twist and slur during the operation of the drive shaft 12.
Next, a description of the closing operation of the above-described gate valve will be given. First, with the gate valve being in the state as shown in FIG. 6 and FIG. 7, air is introduced into the air ports 28 of the direct-acting cylinders 24. When this is done, the shafts 26 begin to rise in the vertical direction, and the power transmission plates 34 and power introducing plates 52 interlocked therewith start to rise. The power transmission plates 34 push up the lower end of the drive shaft 12 by way of the spring parts 36. At this time, the cams 50 are positioned in the upper end side of the holes 54 of the power introducing plates 52. According to the rise of the drive shaft 12, the shaft guide 38 moves along the plates 22 and the bellows 46 contract. Finally, the pulleys 40 of the shaft guide 38 contact the stopper 60 provided in the fitted plate 20 and the rising movement of the drive shaft 12 is completed. As the result, the valve 10 is in a state in which it opposes the flow path port 18.
Next, the shafts 26, power transmission plates 34 and power introducing plates 52 rise. By virtue of this rising movement, the cams 50 roll along the holes 54 of the power introducing plates 52, and the stance of the drive shaft 12 is altered. That is to say, in order for the roll direction of the cams 50 to be inclined with respect to the rise direction of the shafts 26, the drive shaft 12 performs a rotation movement with the pulleys 40 of the shaft guide 38 as its axis. By virtue of this rotation movement, the valve 10 is push-pressured to the side of the flow path port 18. As shown in FIG. 8, as a result of the rotation movement of the drive shaft 12xe2x80x94in the clockwise direction of the diagramsxe2x80x94the valve 10 is seated on the valve seat. At this time, the cams 50 are positioned in the lower end side of the holes 54 of the power introducing plates 52.
Next, a description will be given to the opening operation of the gate valve. In the state shown in FIG. 8, air is introduced into the air port 30 of the direct-acting cylinders 24. When this is done, the shafts 26, power transmission plates 34 and power introducing plates 52 begin to lower. According to this lowering, the cams 50 roll along the holes 54 of the power introducing plates 52 and, then, as described above, the drive shaft 12 is rotated in the anti-clockwise direction in the drawing of FIG. 8. As a result, the valve 10 is separated from the valve seat. At this time, the spring parts 36 have an action whereby they ease or damp the wobble of the drive shaft 12.
Finally, the cams 50 reach the upper end side of the holes 54. At this time, the direction in which the drive shaft 12 extends coincides with the lowering direction of the shafts 26. Thereafter, by the lowering of the shafts 26, the drive shaft 12 and the shaft guide 38 are caused to lower. This lowering movement continues until the pulleys 40 of the shaft guide 38 are in contact with the stoppers 62 of the direct-acting cylinders 24.
As is described above, a conventional gate valve comprises a direct-acting link mechanism in order to move the valve in the direction in which the valve rod extends.
However, in a direct-acting link mechanism, the forces imparted to the valve 10 are determined by the distance between the stoppers 60 and a cam shaft 48 and the shape of the holes 54 of the power introducing plates 52. Because of the action of an inverse pressure on the valve when the gate valve is closed, the force resistant thereto must be imparted to the valve. For this reason, the link mechanism for driving the gate valve may necessarily become large. By way of example, the distance between the stoppers 60 and camshaft 48 must be large so that the above-noted forces are produced. If this is not done, the size of the diameter of the direct-acting cylinders 24 must be made larger.
For this reason, in a vacuum processing device in which a load room, unload room and substrate processing room are arranged in the periphery of a substrate carry room, the structure is such that the gate valve fitted to the above-described rooms juts out below the room lower part surfaces, and the substrate carry room is surrounded by the jutting-out section thereof. With such a configuration, the access space or the maintenance space necessary for regular maintenance and regular check of, for example, the exhaust unit and the drive unit for the substrate carrying arranged in the substrate-carry room lower part, cannot be secured.
Accordingly, the realization of a gate valve apparatus in which the drive unit can be reduced in sizexe2x80x94from that of the prior artxe2x80x94has been desired.
An object of the invention of the present application is to provide a gate valve apparatus in which the reduction in size of the gate valve can be achieved so as to make a reduction in weight of the gate valve and a reduction in manufacturing costs of the gate valve apparatus.
According to the invention, a gate valve apparatus comprises: a valve box with a flow path port; a valve housed in the inner side of the valve box which is employed in the opening and closing of the flow path port; a valve rod connected to the valve; and an open/close mechanism which affords the operation of this valve rod in that it performs a closing operation, whereby the valve is caused to be seated on the valve seat of the valve box, and an opening operation, whereby the valve is caused to be separated from said valve seat, wherein the valve is configured so as to have a swingling motion with the valve rod as its axis, and the open/close mechanism is a link mechanism configured from only a turning pair.
In the preferable embodiment of the gate valve apparatus of the present invention, the open/close mechanism may comprise a link, as a drive joint, which performs a swinging motion.
In another preferable embodiment of the gate valve apparatus of the present invention, the open/close mechanism may further comprise: a first swing link as a drive joint for performing a swinging motion; a second swing link connected to the valve rod which performs a swinging motion with the valve rod as its axis; and a coupling link which couples the first and second swing links.
With such a construction, the opening and closing of the flow path is performed by the swinging motion of the valve with the valve rod as its axis. The open/close mechanism which operates the valve rod is configured from only a turning pair. In a link mechanism configured from only a turning pair in this way, comparatively large forces can be generated even if it is of a small scale. Accordingly, a gate valve of smaller scale than the prior art can be provided.
It will be noted that the pair refers to, of the link from which the mechanism is configured, a combination of two links next to each other. The turning pair refers to a pair which rotate only around one center axis.
Furthermore, in the gate valve of the invention, it may be preferably that the valve rod comprises a kneeshaped (xe2x80x9c less than xe2x80x9d-shaped) bent section wherein this bent section is inserted into a rotation-correspondent bellows which couples the valve box and open/close mechanism, and the structure of this rotation-correspondent bellows is of two directly connected bellows.
Since a rotation-correspondent bellows of a configuration such as mentioned above is employed, the buckling of the bellows caused by the rotation movement of the valve rod can be prevented.